The present invention relates to novel bis-N,N'-amino benzoyl amines and aminophenols and bis-N,N'-nitro benzoyl amine and aminophenyl intermediate compounds. The amino compounds are useful as crosslinking agents and for the preparation of thermally stable polyamides, polyimides, polyamide-imides, and polybenzoxazole polymers.
Aromatic diamines having the structure NH.sub.2 --R--NH.sub.2, where R is a substituted or unsubstituted aromatic moiety have long been known in the art as crosslinking agents for epoxy resins and for unsaturated elastomers, and as reactants in the preparation of polyamides, polyimides and polybenzoxazoles. For example, U.S. Pat. No. 4,111,906 discloses 2,2-bis[4-(4-nitrophenoxy)phenyl]hexafluoropropane which is used as an intermediate in the production of the corresponding amine, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane. This latter monomer is used in reaction with a dianhydride or a diacid to produce a polyimide or polyamide resin respectively. UK Patent Application GB2188936 A discloses the use of diaminophenols such as 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane to prepare aromatic polyamides by reaction with aromatic dicarboxylic acids, followed by cyclization of the polyamide to form a polybenzoxazole. Similar polyamides and polybenzoxazoles are also disclosed in U.S. Pat. No. 4,339,521.
European Patent Specification 0110420 discloses bis(aminophenols) used as curing agents for nitrile-containing perfluoroelastomers. A preferred aminophenol is 4,4'[2,2,2-trifluoro-1-(trifluoromehtyl)-ethylidene]bis(2-aminophenol), which is prepared by nitrating the corresponding bisphenol, followed by catalytic hydrogenation to reduce the dinitro intermediate to the diamine.
While the aforementioned diamines and aminophenols are useful in the applications taught in the prior art, there is a continuing need for new aminophenyl or aminocarboxy phenyl monomers which give rise to unusual and improved crosslinking properties as well as new polyamide, polyimide, and polybenzoxazole polymers exhibiting improved thermal properties, thermal flow properties and flexibility.